Cooling or heating systems in various different devices include a flow channel member including a substrate including a flow channel through which a fluid flows inside thereof. When a low-temperature or high-temperature fluid is caused to flow through the flow channel of the flow channel member, heat is exchanged between an object external to the substrate and the fluid flowing inside the substrate with the substrate interposed therebetween, so that the object can be cooled or heated. For example, when an object is a high temperature gas resulting from operations of various devices, a low temperature liquid is caused to flow through the flow channel and the high temperature gas, which is the object, is brought into contact with the outer surface of the substrate to exchange heat with the low temperature liquid, so that the high temperature gas, or the object, is cooled.
In some cases, a highly corrosive fluid is used as the above-described high temperature gas or low temperature liquid. In addition, the flow channel member itself is required to be durable for long term use. In response to these requirement, flow channel members including a substrate made of a ceramic, having high corrosion resistance and high mechanical characteristics, have been developed (see, for example, PTL 1).